1 /*-
2 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
3 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
15 * Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
24 *
25 * Authors:
26 * Rickard E. (Rik) Faith <faith@valinux.com>
27 * Gareth Hughes <gareth@valinux.com>
28 *
29 */
30
31 /** @file drm_auth.c
32 * Implementation of the get/authmagic ioctls implementing the authentication
33 * scheme between the master and clients.
34 */
35
36 #include "drmP.h"
37
drm_hash_magic(drm_magic_t magic)38 static int drm_hash_magic(drm_magic_t magic)
39 {
40 return magic & (DRM_HASH_SIZE-1);
41 }
42
43 /**
44 * Returns the file private associated with the given magic number.
45 */
drm_find_file(struct drm_device * dev,drm_magic_t magic)46 static struct drm_file *drm_find_file(struct drm_device *dev, drm_magic_t magic)
47 {
48 drm_magic_entry_t *pt;
49 int hash = drm_hash_magic(magic);
50
51 DRM_SPINLOCK_ASSERT(&dev->dev_lock);
52
53 for (pt = dev->magiclist[hash].head; pt; pt = pt->next) {
54 if (pt->magic == magic) {
55 return pt->priv;
56 }
57 }
58
59 return NULL;
60 }
61
62 /**
63 * Inserts the given magic number into the hash table of used magic number
64 * lists.
65 */
drm_add_magic(struct drm_device * dev,struct drm_file * priv,drm_magic_t magic)66 static int drm_add_magic(struct drm_device *dev, struct drm_file *priv,
67 drm_magic_t magic)
68 {
69 int hash;
70 drm_magic_entry_t *entry;
71
72 DRM_DEBUG("%d\n", magic);
73
74 DRM_SPINLOCK_ASSERT(&dev->dev_lock);
75
76 hash = drm_hash_magic(magic);
77 entry = malloc(sizeof(*entry), DRM_MEM_MAGIC, M_ZERO | M_NOWAIT);
78 if (!entry)
79 return ENOMEM;
80 entry->magic = magic;
81 entry->priv = priv;
82 entry->next = NULL;
83
84 if (dev->magiclist[hash].tail) {
85 dev->magiclist[hash].tail->next = entry;
86 dev->magiclist[hash].tail = entry;
87 } else {
88 dev->magiclist[hash].head = entry;
89 dev->magiclist[hash].tail = entry;
90 }
91
92 return 0;
93 }
94
95 /**
96 * Removes the given magic number from the hash table of used magic number
97 * lists.
98 */
drm_remove_magic(struct drm_device * dev,drm_magic_t magic)99 static int drm_remove_magic(struct drm_device *dev, drm_magic_t magic)
100 {
101 drm_magic_entry_t *prev = NULL;
102 drm_magic_entry_t *pt;
103 int hash;
104
105 DRM_SPINLOCK_ASSERT(&dev->dev_lock);
106
107 DRM_DEBUG("%d\n", magic);
108 hash = drm_hash_magic(magic);
109
110 for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
111 if (pt->magic == magic) {
112 if (dev->magiclist[hash].head == pt) {
113 dev->magiclist[hash].head = pt->next;
114 }
115 if (dev->magiclist[hash].tail == pt) {
116 dev->magiclist[hash].tail = prev;
117 }
118 if (prev) {
119 prev->next = pt->next;
120 }
121 free(pt, DRM_MEM_MAGIC);
122 return 0;
123 }
124 }
125
126 return EINVAL;
127 }
128
129 /**
130 * Called by the client, this returns a unique magic number to be authorized
131 * by the master.
132 *
133 * The master may use its own knowledge of the client (such as the X
134 * connection that the magic is passed over) to determine if the magic number
135 * should be authenticated.
136 */
drm_getmagic(struct drm_device * dev,void * data,struct drm_file * file_priv)137 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
138 {
139 static drm_magic_t sequence = 0;
140 struct drm_auth *auth = data;
141
142 /* Find unique magic */
143 if (file_priv->magic) {
144 auth->magic = file_priv->magic;
145 } else {
146 DRM_LOCK();
147 do {
148 int old = sequence;
149
150 auth->magic = old+1;
151
152 if (!atomic_cmpset_int(&sequence, old, auth->magic))
153 continue;
154 } while (drm_find_file(dev, auth->magic));
155 file_priv->magic = auth->magic;
156 drm_add_magic(dev, file_priv, auth->magic);
157 DRM_UNLOCK();
158 }
159
160 DRM_DEBUG("%u\n", auth->magic);
161
162 return 0;
163 }
164
165 /**
166 * Marks the client associated with the given magic number as authenticated.
167 */
drm_authmagic(struct drm_device * dev,void * data,struct drm_file * file_priv)168 int drm_authmagic(struct drm_device *dev, void *data,
169 struct drm_file *file_priv)
170 {
171 struct drm_auth *auth = data;
172 struct drm_file *priv;
173
174 DRM_DEBUG("%u\n", auth->magic);
175
176 DRM_LOCK();
177 priv = drm_find_file(dev, auth->magic);
178 if (priv != NULL) {
179 priv->authenticated = 1;
180 drm_remove_magic(dev, auth->magic);
181 DRM_UNLOCK();
182 return 0;
183 } else {
184 DRM_UNLOCK();
185 return EINVAL;
186 }
187 }
188